The U.S. Department of Agriculture is poised to finalize major changes to the poultry slaughter-inspection process that critics warn could threaten food safety and harm workers.

The proposed rule would allow companies to speed up production lines from 35 birds per minute per inspector to 175 per minute, a five-fold increase. It also would cut hundreds of federal inspector jobs and turn over much of the responsibility for spotting defective or diseased birds to plant employees.

The agency says that the proposal, which has been in the works for more than a decade, reduces the risk of food-borne illness by relying on scientific testing to screen carcasses, rather than the naked eye.

Under the rule, one inspector would be stationed at the end of every production line to eyeball chicken carcasses as they whiz by on hooks. Plant employees, rather than federal inspectors, would cull defective birds farther up the line. USDA officials say that frees up the agency’s remaining workforce to perform more important tasks elsewhere in plants, such as random testing for pathogens and monitoring of sanitation.

Inspectors shouldn’t be doing quality-control tasks that have little to do with protecting public health, said Elisabeth Hagen, the undersecretary for food safety at the USDA.

“There’s a role for visual inspection, but in this day and age it can’t be the only way that we define inspection for food safety,” Hagen said. “We’re not doing the right thing by the consumer if we do that.”

The USDA estimates that the changes will save taxpayers $90 million over three years and $256 million in production costs annually.

Industry proponents say the new rule will modernize the poultry inspection system, which hasn’t been updated much since the 1950s.

“Look at the data. This is not something that USDA cooked up overnight,” said Tom Super, a spokesman for the National Chicken Council. “This has been in a pilot program for 13 years.”

Twenty broiler-chicken plants have volunteered as “trial plants” to test the proposal since 1999. The food-safety and worker-safety records in the plants are on par or better than those plants participating in traditional inspection, Super said.

“Chicken companies and their employees on this line have every incentive to not let a product with a quality defect into the marketplace,” he said.

Super points out that plants in other countries already run much faster. In Germany and Belgium, for example, line speeds typically reach 225 birds per minute, Super said. In Canada, the maximum speed is 250, he said.

Federal poultry inspectors protest that they can’t see bruises, blisters, tumors, pus, broken bones and other signs of tainted birds when carcasses fly by them at a rate of a third of a second. They can’t look inside the birds for bile, partially digested feed or fecal matter, or examine entrails for diseases such as avian leukosis – contaminants that inspectors say can be disgusting at best and dangerous at worst.

“The rule continuously talks about how much money per pound the plants are going to save by going into this process,” said Stan Painter, the chairman of the National Joint Council of Food Inspection Locals, a union that represents about 6,500 federal inspectors. “Why the hell is an agency concerned about the money that the plant’s going to save? I realize that’s a stakeholder, but our focus should be food safety.”

For Painter, who works as a USDA poultry inspector at a pilot plant in Crossville, Ala., opposition to the rule is personal as well as professional. He suffers from reactive arthritis after eating what he thinks was food tainted with salmonella or campylobacter bacteria at a sports event this summer in Texas.

After days of fever, headaches and diarrhea, Painter had lost 9 pounds and developed such painful swelling in his joints that he couldn’t even walk the 100 yards from his house to his mailbox. He said a doctor told him the condition likely was caused by food-borne bacteria, although it was too late to isolate which ones.

“People don’t realize – I didn’t realize – that you can get (arthritis) from eating something,” Painter said.

He and other union officials say his health troubles underscore the urgency of their longtime fight against the USDA’s proposed rule, which they believe will make chicken less safe for consumers by semi-privatizing poultry inspection.

Fewer federal inspectors in plants means fewer police on the beat, and more opportunities for plants to cut corners, Painter said. “If I know the cops are not going to be on the road in 50 miles, I’m gonna speed,” he added.

“The agency is looking at taking 817 inspectors off the poultry lines. I can’t imagine anything worse than that,” said Trent Berhow, a poultry inspector in St. Joseph, Mo., who’s the vice chairman of the union.

“A lot of people would say, ‘They’re just union blowhards thinking about jobs.’ No, we’re not,’ ” Berhow said. “We’re thinking about lives. . . . It’s not about jobs. It is about food safety.”

A risk assessment of the new rule conducted by the USDA found that the rate of fecal-matter contamination at plants in the pilot program is about half that in other plants, and salmonella rates average about 80 percent lower. Equivalent data for campylobacter isn’t available, the agency said.

But USDA statistics also show that salmonella rates have been going up in recent years at pilot plants, while decreasing at non-pilot plants. In 2010, the rate was slightly higher at the pilot plants than at the traditional plants the USDA used for comparison.

Consumer advocates say the trend is disturbing. They’re particularly troubled because the proposed rule no longer would require plants to test for E. coli bacteria or any specific pathogens – not even salmonella or campylobacter. Nor would plants have to meet specific time and temperature parameters for chilling chicken before shipping it to stores. Those details would be determined by each plant, rather than by government regulations.

“They are leaving it up to the plant to decide what to test for, how frequently to test and then to design its own testing plan,” said Chris Waldrop, the director of the Food Policy Institute at the Consumer Federation of America. “It’s shocking, frankly.”

Hagen said the USDA’s proposal removed requirements that weren’t necessarily effective. Ultimately, plants still must meet the agency’s safety standards for acceptable levels of pathogen contamination in birds, she said. “Giving them a little bit of flexibility in terms of how they do that is certainly not going to be harmful to consumers,” she added.

Hagen said the USDA would continue to conduct its own tests for salmonella and campylobacter at the plants.“Even our best inspectors can’t see salmonella. You could give them a third of a second, you could give them a million seconds, and they’re not going to see salmonella,” Hagen said. “We have to make sure that our resources are focused on all the steps we can take to prevent contamination from entering the food supply.”

Four members of Congress sent a letter this month to Agriculture Secretary Tom Vilsack, urging him to withdraw or delay the rule.

“While the poultry slaughter-inspection program does need to be modernized, we are concerned the proposal could have deleterious impacts on both food safety and worker safety,” read the letter signed by Sens. Kirsten Gillibrand, D-N.Y., Richard Blumenthal, D-Conn., and Jeff Merkley, D-Ore., and U.S. Rep. Chellie Pingree, D-Maine.

Public comment on the proposed rule ended in May. The agency is preparing the final version for presentation to the Office of Management and Budget, which will have 90 days to review it.